The bacterial signaling molecule cyclic diguanosine monophosphate (c-di-GMP) is increasingly recognized as having widespread consequences for human health through its multiple roles. Not only is c-di-GMP a major factor in the activation of bacterial biofilm formation and repression of motility, it also helps to regulate virulence. Further, although c-di-GMP is not a signaling molecule in Eukarya, it has been shown to be an immunostimulatory agent that can trigger the innate immune response in mice. The mechanisms for how c-di-GMP function remain unclear. Accordingly, analogs of c-di-GMP are needed.